Archive for the ‘condensation’ category

Insulation Near a Fireplace?

December 17th, 2013

Question:

Can I insulate the underside of my first-floor fireplace chase? I would like to put batt-insulation, and a ceiling below the fireplace. I currently use the area as a storage closet. The area is very cold, and the air seems to migrate upstairs. I also get frost above the basement wall, on the framing. The fireplace is ~20 years old, and non-gas.

–Eric

Answer:

You’ll need to check on the installation requirements for your specific type of pre-fabricated fireplace. They must be installed per specific installation requirements. In general, they require clearance around the metal firebox, and around the metal flue that is routed up through the boxed-in chimney chase. I don’t think your real problem is in the basement. I think the real problem is the exterior wall behind the fireplace. Insulating below the floor will be of little value.

The areas around the fireplace can be a big heat-loss, because the outside wall behind the fireplace may not be properly insulated. The exterior wall should be framed so that it can be insulated and sealed like a typical exterior wall. This does not always happen when the wall is buried behind a manufactured fireplace, and brick facing.

F007 - Metal-Framed Prefabricated FireplaceThe area below the fireplace (above the foundation wall) should be independent from the fireplace installation. Ice in this area (and around the sill/band joist) occurs because air moves through the fiberglass batts, and moisture condenses on the cold surface.

The ideal fix at the top of the foundation wall is to have the area sealed and insulated with spray foam. This will seal the air-leaks, provide a vapor-barrier, and insulate the area.

If you want to work with fiberglass, you need to remove it and caulk any gaps in the area around the sill-plate to the sub-floor. Fill the space with tight-fitting fiberglass, then seal it with drywall and plastic caulked in place on the heated side. It sounds like the foam is a much better option.

–Mr. Fix-It

Leaks Coming From the Attic

November 18th, 2013

Question:

I have frost in the attic of my five-year old, two-story house. I noticed a small leak coming out of the can light in the bathroom. Do I have enough insulation in my attic? I have 2″ x 4″ ceiling rafters, with ~16 inches of blown-in white insulation. I also have a ridge-vent running along the peak. Could heat be exiting through the attic door, exhaust vents, or can light, then melting the frost?

–Kevin

Answer:

Most folks who study moisture and home systems would identify your issue as an air-leak problem into the attic. Warm, moist air from the heated space is escaping into the attic, and moisture from that air is condensing on the cold roof deck. This may show as ice in very cold weather, and water in warmer weather. The problem is not insulation.

 

I025 - Air Leaks - Top of Wall

You need to search for air leaks at can lights, plumbing, electrical penetrations, chimneys, trap doors, etc. Seal up the air leaks, and the problem will be solved. Sounds easy? It’s not. You need an experienced contractor, who knows how to locate and seal the leaks. However, stopping theair leaks will save lots of energy.

I suspect you saw the leak at the can light because the light heat was melting the frost. The plastic vapor barrier is also open at the can light. If you want more information on attic insulation and air sealing, read my article Insulate Your Attic – But Don’t Stop There!

–Mr. Fix-It

Discoloration on Wood Windows

March 6th, 2013

QUESTION

We have a black discoloration occurring on the wood windows in our house; I was wondering if you knew what it was, and how to get rid of it. The windows are double-hung, and the house was built in 1995. I assumed it was mold and moisture-related, because I noticed it in the bathroom. But, I have since found it in small patches on other windows, both upstairs and downstairs. I have tried many cleaning solutions, including TSP and a bleach/water mix, but none seem to work. Any ideas or suggestions would be greatly appreciated.

BURNS

ANSWER

If the stains are a dark discoloration that cannot be removed from the surface, you have water damage in the wood of the window. If the TSP removes the stain, it may be dirt or mold. Once the surface finish is damaged by water, the water will discolor the wood. So, if the finish is gone and you have a dark stain, you have water damaged wood.The fix is to refinish the wood by sanding, bleaching, and more sanding. Then, stain and varnish to back to the original finish. Not an easy job.

MR. FIX-IT

Condensation on Storms

February 3rd, 2010

Question:

I have 12-year-old Kolbe double-hung windows. One set of windows in a 2nd floor bedroom has had exterior condensation on the inside upper-half of the storm window (not the actual double-hung itself). In cold weather this will ice/frost over.

What does this indicate? Is it a problem? Assuming it is an interior leak, how would I figure out where the source is?

Answer:

Condensation on the inside of the storms is caused by warm, moist air leaking from the inside of the home around the interior, primary windows into the space between the primary window and storm. Once the moist air is there, the moisture condenses on the storms – the coldest surface.

This is a common problem and unless it is excessive, quite normal. There is no easy fix. You can try to seal the inner, primary window, reduce the humidity level in your home, or even open the storm a little to vent out the moisture.

You can find more information here:
Fogged Up? Clearing the Air About Window Condensation Problems

Moisture Problems Inside the Home

January 20th, 2010

We have a rental house with home humidity above 60%. The dehumidifier in the basement frosts up. Renters tell me that their clothes smell musty from the dampness, and the windows have condensation. The north side of the house is cold. The house was built around 1957. We want to correct the problem, but don’t know what to do. We have had several furnace contractors give us recommendations such as tiling the exterior of the foundation and grading away from the house. What is the best solution?

Pamela

You are describing all the problems with excessive moisture in a home during cold weather. You can find a complete analysis along with steps for solving your problem on the Free PDF Articles page. Here’s a link to the article:

Fogged Up? Clearing the Air About Window Condensation Problems.

You need to look for the sources of the problem – a damp basement, plumbing leak, clothes dryer, back-drafting gas appliance, plants, cooking, a humidifier, etc. Eliminating the source should solve the problem.

You should also consider ventilation. Bath and kitchen fans tend to remove excessive spot moisture. People are also a big source of indoor moisture (people, pets, plants).

Leaky Bathroom Fan – Drip, Drip, Drip

December 30th, 2009

Question:

I have a bathroom exhaust fan that is vented into the attic, up to the ridge-vent area. Since the weather had gotten colder, water drips back into the bathroom from the fan after it has been on for a while. Do I need a certain type of material for the vent? Should I insulate it? I’m not sure what the solution is. Thanks for your help.

Glen

Answer:

Your problem is condensation in the cool fan duct. Warm, moist air from the bathroom condenses on the cool duct and runs down the duct to the fan. The duct is now cold because the attic is cold.

The duct should be insulated. Make as short of a run as possible to a vent connector through the roof deck. The fan duct should not be run to the ridge-vent. You can find insulated duct and a vent connectors at a building supply store.

The fan and the vent connector through the roof should also have a damper that closes when the fan is off to limit air movement.

Tom

Condensation on East Windows – Not West?

December 16th, 2009

Saturday I listened to you talk about moisture on windows and looked the article up on your website. I have a question. What if some windows get moisture and some do not? We have a 16-year-old house – two story. The bedroom window on the east side of the house gets moisture (always has), but the bedroom window on the west side of the house does not. After reading the article I learned a lot, but I just have this other question. Thank you so much.

-Sue

Answer:

Wind Pushes Air Through a HomeWhen warm, moist air contacts a cold surface, you have condensation (just like moisture on that iced-tea glass in the summer).

I assume you are getting condensation on the storm window. Wind blows at your house, and in the Milwaukee area it often blows from the west to the east. On the west side of your home, cold air is blown in around the storm and leaks into your home. The air blowing in is very dry and there is no condensation.

On the west side of your home warm, moist air is leaking out of the windows and you have condensation on the cold storms. The storms trap the warm air and the storm glass is cold.

For folks that want more information, look at my website article “Fogged Up? Clearing the Air About Window Condensation Problems.”

-Tom

Condensation on Storm Windows

December 4th, 2009

Question:

Condensation on WindowsI have a 12 year old Kolbe double hung window. One set of windows in a 2nd floor bedroom has had exterior condensation on the inside upper half of the storm window (not the actual double-hung itself). In cold weather this will ice/frost over.

What does this indicate? Is it a problem? If I should fix it, assuming it is an interior leak, how would I figure out where the source is? Thanks in advance.

-Chris

Answer:

Sources of MoistureCondensation on the inside of the storms is caused by warm, moist air leaking from the inside of the home around the interior, primary windows into the space between the primary window and storm.  Once the moist air is there, the moisture condenses on the storms – the coldest surface.

This is a common problem and unless it is excessive, quite normal. There is no easy fix.  You can try to seal the inner, primary window, reduce the humidity level in your home, or even open the storm a little
to vent out the moisture.

You can find more information in my PDF article – Fogged Up? Clearing the Air About Window Condensation Problems.

-Tom